diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-02 18:38:16 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-02 18:38:16 +0200 |
commit | 99c6bcf46d2233d33e441834e958ed0bc22b190a (patch) | |
tree | 25abf5e856bc0f08d75e623715eb5acc4d4de2b2 /arch/arm/mach-spear/time.c | |
parent | Merge tag 'soc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ar... (diff) | |
parent | mmc: sdhci-s3c: Fix operation on non-single image Samsung platforms (diff) | |
download | linux-99c6bcf46d2233d33e441834e958ed0bc22b190a.tar.xz linux-99c6bcf46d2233d33e441834e958ed0bc22b190a.zip |
Merge tag 'multiplatform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC multiplatform updates from Olof Johansson:
"More multiplatform enablement for ARM platforms. The ones converted
in this branch are:
- bcm2835
- cns3xxx
- sirf
- nomadik
- msx
- spear
- tegra
- ux500
We're getting close to having most of them converted!
One of the larger platforms remaining is Samsung Exynos, and there are
a bunch of supporting patches in this merge window for it. There was
a patch in this branch to a early version of multiplatform conversion,
but it ended up being reverted due to need of more bake time. The
revert commit is part of the branch since it would have required
rebasing multiple dependent branches and they were stable by then"
* tag 'multiplatform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (70 commits)
mmc: sdhci-s3c: Fix operation on non-single image Samsung platforms
clocksource: nomadik-mtu: fix up clocksource/timer
Revert "ARM: exynos: enable multiplatform support"
ARM: SPEAr13xx: Fix typo "ARCH_HAVE_CPUFREQ"
ARM: exynos: enable multiplatform support
rtc: s3c: make header file local
mtd: onenand/samsung: make regs-onenand.h file local
thermal/exynos: remove unnecessary header inclusions
mmc: sdhci-s3c: remove platform dependencies
ARM: samsung: move mfc device definition to s5p-dev-mfc.c
ARM: exynos: move debug-macro.S to include/debug/
ARM: exynos: prepare for sparse IRQ
ARM: exynos: introduce EXYNOS_ATAGS symbol
ARM: tegra: build assembly files with -march=armv7-a
ARM: Push selects for TWD/SCU into machine entries
ARM: ux500: build hotplug.o for ARMv7-a
ARM: ux500: move to multiplatform
ARM: ux500: make remaining headers local
ARM: ux500: make irqs.h local to platform
ARM: ux500: get rid of <mach/[hardware|db8500-regs].h>
...
Diffstat (limited to 'arch/arm/mach-spear/time.c')
-rw-r--r-- | arch/arm/mach-spear/time.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/arch/arm/mach-spear/time.c b/arch/arm/mach-spear/time.c new file mode 100644 index 000000000000..d449673e40f7 --- /dev/null +++ b/arch/arm/mach-spear/time.c @@ -0,0 +1,245 @@ +/* + * arch/arm/plat-spear/time.c + * + * Copyright (C) 2010 ST Microelectronics + * Shiraz Hashim<shiraz.hashim@st.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/ioport.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/time.h> +#include <linux/irq.h> +#include <asm/mach/time.h> +#include "generic.h" + +/* + * We would use TIMER0 and TIMER1 as clockevent and clocksource. + * Timer0 and Timer1 both belong to same gpt block in cpu subbsystem. Further + * they share same functional clock. Any change in one's functional clock will + * also affect other timer. + */ + +#define CLKEVT 0 /* gpt0, channel0 as clockevent */ +#define CLKSRC 1 /* gpt0, channel1 as clocksource */ + +/* Register offsets, x is channel number */ +#define CR(x) ((x) * 0x80 + 0x80) +#define IR(x) ((x) * 0x80 + 0x84) +#define LOAD(x) ((x) * 0x80 + 0x88) +#define COUNT(x) ((x) * 0x80 + 0x8C) + +/* Reg bit definitions */ +#define CTRL_INT_ENABLE 0x0100 +#define CTRL_ENABLE 0x0020 +#define CTRL_ONE_SHOT 0x0010 + +#define CTRL_PRESCALER1 0x0 +#define CTRL_PRESCALER2 0x1 +#define CTRL_PRESCALER4 0x2 +#define CTRL_PRESCALER8 0x3 +#define CTRL_PRESCALER16 0x4 +#define CTRL_PRESCALER32 0x5 +#define CTRL_PRESCALER64 0x6 +#define CTRL_PRESCALER128 0x7 +#define CTRL_PRESCALER256 0x8 + +#define INT_STATUS 0x1 + +/* + * Minimum clocksource/clockevent timer range in seconds + */ +#define SPEAR_MIN_RANGE 4 + +static __iomem void *gpt_base; +static struct clk *gpt_clk; + +static void clockevent_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk_event_dev); +static int clockevent_next_event(unsigned long evt, + struct clock_event_device *clk_event_dev); + +static void spear_clocksource_init(void) +{ + u32 tick_rate; + u16 val; + + /* program the prescaler (/256)*/ + writew(CTRL_PRESCALER256, gpt_base + CR(CLKSRC)); + + /* find out actual clock driving Timer */ + tick_rate = clk_get_rate(gpt_clk); + tick_rate >>= CTRL_PRESCALER256; + + writew(0xFFFF, gpt_base + LOAD(CLKSRC)); + + val = readw(gpt_base + CR(CLKSRC)); + val &= ~CTRL_ONE_SHOT; /* autoreload mode */ + val |= CTRL_ENABLE ; + writew(val, gpt_base + CR(CLKSRC)); + + /* register the clocksource */ + clocksource_mmio_init(gpt_base + COUNT(CLKSRC), "tmr1", tick_rate, + 200, 16, clocksource_mmio_readw_up); +} + +static struct clock_event_device clkevt = { + .name = "tmr0", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = clockevent_set_mode, + .set_next_event = clockevent_next_event, + .shift = 0, /* to be computed */ +}; + +static void clockevent_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk_event_dev) +{ + u32 period; + u16 val; + + /* stop the timer */ + val = readw(gpt_base + CR(CLKEVT)); + val &= ~CTRL_ENABLE; + writew(val, gpt_base + CR(CLKEVT)); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + period = clk_get_rate(gpt_clk) / HZ; + period >>= CTRL_PRESCALER16; + writew(period, gpt_base + LOAD(CLKEVT)); + + val = readw(gpt_base + CR(CLKEVT)); + val &= ~CTRL_ONE_SHOT; + val |= CTRL_ENABLE | CTRL_INT_ENABLE; + writew(val, gpt_base + CR(CLKEVT)); + + break; + case CLOCK_EVT_MODE_ONESHOT: + val = readw(gpt_base + CR(CLKEVT)); + val |= CTRL_ONE_SHOT; + writew(val, gpt_base + CR(CLKEVT)); + + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + + break; + default: + pr_err("Invalid mode requested\n"); + break; + } +} + +static int clockevent_next_event(unsigned long cycles, + struct clock_event_device *clk_event_dev) +{ + u16 val = readw(gpt_base + CR(CLKEVT)); + + if (val & CTRL_ENABLE) + writew(val & ~CTRL_ENABLE, gpt_base + CR(CLKEVT)); + + writew(cycles, gpt_base + LOAD(CLKEVT)); + + val |= CTRL_ENABLE | CTRL_INT_ENABLE; + writew(val, gpt_base + CR(CLKEVT)); + + return 0; +} + +static irqreturn_t spear_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &clkevt; + + writew(INT_STATUS, gpt_base + IR(CLKEVT)); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction spear_timer_irq = { + .name = "timer", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = spear_timer_interrupt +}; + +static void __init spear_clockevent_init(int irq) +{ + u32 tick_rate; + + /* program the prescaler */ + writew(CTRL_PRESCALER16, gpt_base + CR(CLKEVT)); + + tick_rate = clk_get_rate(gpt_clk); + tick_rate >>= CTRL_PRESCALER16; + + clkevt.cpumask = cpumask_of(0); + + clockevents_config_and_register(&clkevt, tick_rate, 3, 0xfff0); + + setup_irq(irq, &spear_timer_irq); +} + +const static struct of_device_id timer_of_match[] __initconst = { + { .compatible = "st,spear-timer", }, + { }, +}; + +void __init spear_setup_of_timer(void) +{ + struct device_node *np; + int irq, ret; + + np = of_find_matching_node(NULL, timer_of_match); + if (!np) { + pr_err("%s: No timer passed via DT\n", __func__); + return; + } + + irq = irq_of_parse_and_map(np, 0); + if (!irq) { + pr_err("%s: No irq passed for timer via DT\n", __func__); + return; + } + + gpt_base = of_iomap(np, 0); + if (!gpt_base) { + pr_err("%s: of iomap failed\n", __func__); + return; + } + + gpt_clk = clk_get_sys("gpt0", NULL); + if (!gpt_clk) { + pr_err("%s:couldn't get clk for gpt\n", __func__); + goto err_iomap; + } + + ret = clk_prepare_enable(gpt_clk); + if (ret < 0) { + pr_err("%s:couldn't prepare-enable gpt clock\n", __func__); + goto err_prepare_enable_clk; + } + + spear_clockevent_init(irq); + spear_clocksource_init(); + + return; + +err_prepare_enable_clk: + clk_put(gpt_clk); +err_iomap: + iounmap(gpt_base); +} |